Characterization of cellulose membranes produced by Acetobacter xyllinum

Abstract

Cellulose membranes formed by Acetobacter xylinum under known cell density in a culture medium were characterized. A dead end testing unit was used for water flux and filtration of Chlorella sp. and bovine serum albumin (BSA). This study found that the cells formed membranes faster in sucrose supplemented coconut juice than in the standard Schramm & Hestrin's medium. For two-day formed membranes in the former medium, an increase in cell density from 1 × 108 to 2 × 108 cfu.ml-1 reduced water flux and, hence, reduced the hydraulic permeability coefficient (Lp) from 3.6 × 10-10 to 0.5 × 10-10 m3N-1s-1. These membranes were asymmetric-hydrophilic type with thickness less than 6.0 μm. Membrane porosity was found to vary from 1.4% to 2.4%, with the averaged pore size 0.08 μm. Under 100 kPa filtration, two-day formed membranes in sucrose supplemented coconut juice with higher cell density rejected Chlorella cells and BSA by 99.8% and 98.4%, respectively.

Keywords

• Acetobacter xylinum
• cellulose membrane
• filtration
• hydraulic permeability
• Chlorella sp.
• BSA